1. Field of the Invention
The present invention generally relates to a scanner with an automatic edge detection capability; more specifically, the present invention relates to a scanner capable of quickly, accurately, and readily detecting the edges of a document or an object to be scanned.
2. Description of the Related Art
As a gift of the modern technology, the scanner has become one of the most important image-inputting devices used by today""s offices. Before the detailed image of a document or an object disposed on the flat glass platform of a conventional scanner is scanned, a pre-scan function is typically incorporated to quickly gather crude information about the object being scanned as disclosed in the U.S. Pat. No. 4,837,635. In other words, the pre-scan function typically produces a low-resolution scanning image displayable on a computer monitor before a more complete image of the object is meticulously scanned. Such pre-scan function of a scanner typically provides a previewing picture and thereby offering a choice to the user for defining a specific region of the object to be scanned zoomed, or processed by other special functions.
Nevertheless, a user executing the aforementioned pre-scan function relies heavily on the processing power of an externally linked computer and monitor such that only an experienced computer user can perform the subsequent zooming or cropping operations manually via a pointing device for accurately defining the boundaries of the object being scanned. For example, as to the ordinary activities of fitting different sizes of zoomed or reduced images to various fixed paper sizes, such as zooming an image from size A3 to size B5, a costly high-end computer system calling for a series of inconvenient manual operations is typically required to accurately produce a zoom image of true size. In particular, although many conventional scanners claim only a very short lapse of time is needed for each pre-scan function to be completed, but in fact the time required for the scanning module in a scanner to obtain a rough image of an object, relative to the overall scanning operation, is very considerable. Namely, an object disposed on a flat glass platform of the scanner is quickly scanned in a line-by-line fashion such that each line of the scanned image is sequentially generated by varying the charges in the charged couple devices (CCDs) of the scanning module. Moreover, the charges in the CCDs must be completely removed after each time a line of the scanned image is""sequentially outputted to make the CCDs available for scanning the next line, which can be very time-consuming. Although an A3-size scanner is becoming a standard equipment in a modern office, the scanning rate of the conventional scanner is still considered inadequate for normal office operations. Especially when said scanner is operated side-by-side with a latest Xerox-type copying machine used strictly or photocopying purposes, it is only more obvious that said scanner will never catch up with said copying machine in speed. Although a scanner, unlike a photocopier, is an equipment used for digitizing document information to be further processed by a computer in graphic forms, it is still nonetheless an important issue for the scanner manufacturers to provide scanners equipped with such time-saving functions as auto zooming and edge detection.
In fact, if the edges of an object to be scanned can be automatically detected by the scanner, the issue of the auto zooming can be overcome without even considering the image of the object itself.
Among the assorted image processing devices, some of the latest photocopiers have already been known to possess the ability for edge detection, which can automatically detect a number of fixed paper sizes. Nonetheless, the edge-detecting operation of the photocopier is different from that of a scanner, described in paragraphs that follow, according to the present invention. A conventional photocopier with the function of-auto zooming, for example, typically comprises a plurality of edge detectors each located at a pre-determined fixed positions under the flat glass platform that corresponds to a specific paper size. Furthermore, the photocopier may have two edge detectors, namely a detector A4 and a detector B5 respectively located under the corresponding borders of A4-size and B5-size zones. Accordingly, if the detector A4 detects that an object or a document is occupying the pre-defined edges of the A4 size zone, the object or the document on the flat glass platform is then determined by the photocopier to be that of the A4 size so that the auto-zooming function for changing between different fixed paper sizes can proceed.
However, because the above-mentioned edge detectors of the photocopier are located at different predetermined and fixed positions that correspond to the specific paper sizes, said photocopier, therefore, can only zoom in or zoom out between the respective fixed paper sizes. If, occasionally, the object on the flat glass platform does not belong to any of the paper sizes pre-defined and thus recognizable by the photocopier, or if the object or the document is placed out of bound of the recommended position, then the edges of the object cannot be determined for a correct selection of the paper sizes, which would inevitably hampers the success of the auto-zooming function. Obviously, the aforementioned auto-zooming function used in a conventional photocopier cannot suitably satisfy the requirements of an automatic edge-detecting scanner capable of auto-zooming an object or a document of arbitrary paper size to a document of fixed paper size such as the A4 or B5 size.
Therefore, it is an object of the present invention is to provide an improved scanner with automatic edge detection capable of quickly and accurately detecting the size of an object placed on the glass platform thereof without the assistance of a computer and a monitor. In particular, the scanner according to the present invention is capable of obtaining the correct size of the object being scanned without restricting the size of the object to match any of the fixed paper sizes in order for such scanner function as auto zooming to proceed successfully.
The present invention achieves the above-indicated objects by providing a scanner with automatic edge detection comprising a main body, a scanning module, and an edge detector. Wherein, the main body includes a flat glass platform for supporting an object to be scanned. The scanning module is installed inside the main body for scanning the object disposed on said glass platform. The edge detector is also installed inside the main body for detecting any edge of the object along a first track.
Accordingly, the first major advantage of using the scanner according to the present invention is that the actual size of the scanned object is quickly and automatically detected by the edge detector installed inside the main body. The edge detector is capable of detecting the edges of the scanned object through quick movements along the first track, or a plurality of edge detectors are fixed inside the main body at locations where the edges of the objects are most likely to be detected. Thus, the size of an object within the scanning range of the scanner is quickly and automatically determined by detecting the edges of the object according to the present invention.
The second major advantage of using the scanner according to the present invention is that, through a microprocessor and a properly embedded computer program, the scanner according to the present invention is capable of auto zooming on the scanned object without the assistance of a computer and a monitor. It means that the scanner according to the present invention is a stand-alone scanning unit capable of saving the overall operating cost.